Painted metal sheet for printing with a sublimation dye

ABSTRACT

A colored metal sheet useful as a decorative member, a multi-colored signboard, etc. is provided by transfer-printing a topcoat or clear paint layer  4  formed on a substrate metal sheet  1  with a sublimation dye. A basecoat paint layer  2  and a primer paint layer  3  may be formed between the substrate metal sheet  1  and the paint layer  4 . A sublimation dye penetrates into the paint layer  4  to form colored parts  5  extending along thickness direction of the paint layer  4 . Glass flakes  6  (of 8 μm or less in thickness and 10-70 μm in length) and calcium silicate (of 1-8 μm in primary particle size) may be dispersed in the paint layer  4 , to improve slippage-proof property and wear-resistance. Powdery silica (of 0.5-8 μm in particle size) may be dispersed in the paint layer  4 , to improve anti-scratching property and wear-resistance. Light-resistance of the paint layer  4  is improved by using a topcoat or clear paint mainly composed of a melamine-containing thermosetting polyester resin having number average molecular weight of 1000-10000 and a glass transition temperature (Tg) of 20-60° C.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of co-pending U.S. patentapplication Ser. No. 09/667,132, filed Sep. 21, 2000, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a painted metal sheet, on whicha printed design full of variety is given with a sublimation dye, foruse as a multi-colored signboard, a decorative interior sheet, adecorative surfacing sheet, a door panel for an elevator or an outerpanel for electric home appliances or furniture, etc.

[0004] 2. Description of Related Art

[0005] Painted metal sheets printed with colorful designs have beenmanufactured so far by offset, silk, photogravure or transfer-printing.In a conventional transfer-printing method, a sublimation dye is appliedto a topcoat or clear paint formed on a painted metal sheet by a properprinting method such as offset, silk, photogravure or transfer. The topclear layer is then impregnated with the sublimation dye by heattreatment. For instance, JP 51-24313A discloses a method wherein atransfer film is heated in contact with a paint layer of thermosettingsynthetic resin. JP 54-104907A discloses a method wherein a paint layerprinted with a sublimation dye is formed on a metal sheet, a top paintlayer is formed on the printed layer, and then the top layer isimpregnated with the sublimation dye from the inner side by heattreatment. JP 7-31931A discloses a method wherein a pre-coated metalsheet, which has a primer paint layer and a colored top paint layer, isimpregnated with a sublimation dye. JP 7-102733A discloses a methodwherein an opaque resin layer formed on a metal sheet is impregnatedwith a sublimable coloring agent.

[0006] In any case, an objective design appears by penetration of thesublimation dye into the top paint layer. However, a conventional clearpaint layer is inferior of anti-scratching property (scratchresistance), wear-resistance and slippage-proof (slippage resistance)property, and scratches formed on its surface are apparentlydistinguished, although it is smooth, glossy and vivid. In thisconsequence, the printed sheet is not applicable to such a part as aflooring sheet or a table counter, which is used under abrasiveconditions.

[0007] Anti-scratching property and wear-resistance of a paint layer canbe improved by addition of an inorganic filler. For instance, JP48-66640A proposes a powdery paint improved in anti-scratching propertyand wear-resistance by addition of glass fibers at a ratio of 5-70 wt.%. JP 51-8128A proposes a paint, which contains glass flakes havingthickness less than 3 μm and a size passing a sieve of 150 meshes, for aprecoated steel sheet improved in anti-scratching property andwear-resistance. JP 8-183926A proposes a painted metal sheet coated withan acrylic resin paint improved in anti-scratching property andwear-resistance by addition of an inorganic filler at a ratio of 5-60parts by weight based on 100 parts by weight of a solid vehicle in apaint. However, these paint layers are poor of transparency to wellintensify a colored design using as a background metallic luster of asubstrate metal or a color tone of an undercoat paint layer and alsoinferior of slippage-proof, although they have good anti-scratchingproperty and wear-resistance. Anti-scratching property andwear-resistance of a paint layer can be improved by addition of aninorganic filler. For instance, JP 48-66640A proposed a powdery paintimproved in anti-scratching property and wear-resistance by addition ofglass fibers at a ratio of 5-70 wt. %. JP 51-8128A proposed a paint,which contains glass flakes having thickness less than 3 μm and a sizepassing a sieve of 150 meshes, for a precoated steel sheet improved inanti-scratching property and wear-resistance. JP 8-183926A proposed apainted metal sheet coated with an acrylic resin paint improved inanti-scratching property and wear-resistance by addition of an inorganicfiller at a ratio of 5-60 parts by weight based on 100 parts by weightof a solid vehicle in a paint. However, these paint layers are poor oftransparency to well intensify a colored design using as a backgroundmetallic luster of a substrate metal or a color tone of an undercoatpaint layer and also inferior of slippage-proof, although they are goodof anti-scratching property and wear-resistance.

[0008] A paint layer is also improved in anti-scratching property andwear-resistance by irradiation with an electron beam, as noted in anelectron beam-curing acrylic paint (as disclosed in JP 55-5422B, JP56-8070B, JP 1-229622A and JP 2-242863A). Since a paint layer irradiatedwith an electron beam has hardness of 9H or harder by a pencil hardnesstest, it has good wear-resistance, anti-scratching property andanti-fouling property. However, such an electron beam-curing paint layeris poor of plasticity and relatively expensive, and also needs a specialelectron beam irradiator for curing the paint layer, resulting inincrease of a manufacturing cost. There is also the disadvantage that apaint layer cured with electron beam irradiation is poor ofwear-resistance, compared with a thermosetting resin layer.

[0009] By the way, vinyl chloride tiles, vinyl chloride panels, etc.,which are commonly used as organic flooring materials are difficult togive a multi-colored design with a sublimation dye due to poordimensional stability and poor heat-resistance. Decorative flooringmaterial, which uses metallic luster of a substrate metal sheet as abackground for a multi-colored design, is scarcely offered to themarket. Most table counters are made of wood, but multi-colored goodswith metallic appearance are scarcely offered to the market.

[0010] Multi-colored decorative signboards have been also manufacturedso far by a short-lot process wherein a decorative film is individuallystuck to a metal sheet or a painted sheet instead of using a sublimationdye. However, such a decorative signboard can not be used for a longterm exceeding a half-year, since the laminated decorative film iseasily peeled off. It is also difficult to increase hardness of thedecorative film for improvement of anti-scratching property, accountingfor lamination of the decorative film at a final stage of themanufacturing process. In addition, external appearance of the signboardis significantly influenced by texture of the decorative film, so thatit is impossible to allot color with metallic or ceramic impression.

[0011] Coloring concentration of a pattern printed with a sublimationdye is limited to a narrow range due to poor masking ability of thesublimation dye. When a heat is applied to a transfer film during atransfer-printing step, a sublimation dye is often excessivelytransferred even to an undercoat paint layer or reversely transferred tothe transfer film. Such unfavorable transfer of the sublimation dyecauses a printed pattern to lack sharpness especially in case ofprinting characters or the like.

[0012] A decorative design is realized by impregnation of a top paintlayer with a sublimation dye in any of conventional design-printingmethods. However, such a sublimation dye is a dispersion-type or oilytype having a small polarity, and is easily degenerated by plasticizersor organic chemicals, and also decomposed by ultraviolet irradiationresulting in discoloration or fading. Due to these unfavorableproperties of the sublimation dye, the decorative design is hardly keptin a stable colored state under conditions exposed to open air for along time. Discoloration or fading caused by ultraviolet irradiation canbe inhibited by addition of a proper ultraviolet-absorbing agent to apaint at a ratio of 0.5-3 wt. % on the basis of a non-volatile componentin the paint.

[0013] A precoated steel sheet as a substrate for transfer-printing ismanufactured by baking an applied paint at 200-240° C. (as a highesttemperature of a substrate sheet) for 1-2 minutes, while a paint layeris impregnated with a sublimation dye at 160-190° C. for 1-4 minutes.That is, the ultraviolet-absorbing agent added to the paint is exposedto a high-temperature atmosphere at least two times until a final stageof a printed metal sheet-manufacturing process. A commonly usedultraviolet-absorbing agent such as benzophenone or benzotriazole isquantitatively decreased in the paint layer due to poor resistance toheat and sublimation. The weight loss of the ultraviolet-absorbing agentputs harmful influences on discoloration or fading of the decorativedesign, but also causes deformation of the paint layer to a yellowishrugged surface. Such yellowish appearance is apparently distinguished,when paint-baking as well as transfer-printing are performed at a highertemperature.

[0014] Weight loss of the ultraviolet-absorbing agent is suppressed byaddition of a thermally-stable and well-soluble benzotriazole ortriazine compound at a ratio of 6-18 wt. % on the basis of anon-volatile component in a paint, as disclosed in JP 9-206678A.Addition of such a benzotriazole or triazine compound is effective formany kinds of sublimation dyes, but discoloration or fading of somesublimation dyes can not be suppressed to a level necessary for outdoorapplication. Although discoloration or fading may be suppressed by usinga high-grade sublimation dye for good light resistance, change of thesublimation dye is not a practical idea accounting constraint onaptitude, color tone, etc. of the sublimation dye in correspondence witha type of a printer used for outputting a decorative image. Forinstance, if only one color ink is poor of light-resistance among basic4 colors (cyanic, magenta, yellow and black), a printed sheet can not beused for outdoor application.

SUMMARY OF THE INVENTION

[0015] The present invention is accomplished to overcome the problems asabove-mentioned, and aims at providing a painted metal sheet, to which amulti-colored design can be given without eliminating metallic luster ofa substrate metal sheet or a color tone of an undercoat paint layer, andalso improved in light-resistance, anti-scratching property,wear-resistance, slippage-proof property and anti-fouling property.

[0016] Slippage-proof property and wear-resistance of a transparent ortranslucent topcoat paint layer are improved by dispersion of glassflakes and calcium silicate in the paint layer. The topcoat paint layeris formed from a paint containing glass flakes at 5-25 wt. % and calciumsilicate at 0.5-10 wt. % on the basis of a non-volatile component in thepaint. The glass flakes are of 10-70 μm in average length, while thecalcium silicate is of 1-8 μm in average primary particle size. Thetopcoat paint layer has thickness of 5-40 μm and surface roughness ofRa: 1.0-6.0 μm. A decorative design is given to the topcoat paint layerby impregnation with a sublimation dye.

[0017] Anti-scratching property and wear-resistance of a topcoat orclear paint layer are improved by dispersion of powdery silica in thepaint layer. Powdery silica of 0.5-8 μm in average particle size isdispersed in the clear paint layer at a ratio of 1-10 wt. % on the basisof a non-volatile component in the paint, and the clear paint layer iscontrolled to thickness of 5-40 μm and 60-degree glossiness of 10-75.

[0018] Discoloration and fading of a sublimation dye can be remarkablysuppressed by use of a resin good of light-resistance. In this case, atopcoat paint layer is formed from a transparent or translucent paintmainly composed of a thermosetting polyester resin having number averagemolecular weight of 1000-10000 and a glass transition temperature (Tg)of 20-60° C. and containing melamine at a ratio of 20-150 parts byweight on the basis of 100 parts by weight of a solid component in thepaint.

[0019] The thermosetting polyester resin may be preferably one whichcontains a 1,2-benzene-dicarbonyl structure derived from a dicarboxylicacid monomer and/or a 2,2-dimethyl trimethylene structure derived from adi-alcoholic monomer in its molecule.

[0020] A triazine and/or benzotriazole ultraviolet-absorbing agent maybe added to the topcoat paint preferably at a ratio of 1-22 parts byweight on the basis of 100 parts by weight of a non-volatile componentin the paint.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1A is a sectional view of a metal sheet coated with abasecoat paint layer and a transparent or translucent paint layer towhich a colored design is given by transfer-printing in Example 1;

[0022]FIG. 1B is a sectional view of a metal sheet coated with a primerlayer, a basecoat paint layer and a transparent or translucent paintlayer to which a colored design is given by transfer-printing in Example1;

[0023]FIG. 1C is a sectional view of a metal sheet directly coated witha transparent or translucent paint layer to which a colored design isgiven by transfer-printing in Example 1;

[0024]FIG. 2A is a sectional view of a metal sheet coated with abasecoat paint layer and a clear paint layer to which a colored designis given by transfer-printing in Example 3;

[0025]FIG. 2B is a sectional view of a metal sheet coated with abasecoat layer, a primer paint layer and a clear paint layer to which acolored design is given by transfer-printing in Example 3;

[0026]FIG. 2C is a sectional view of a metal sheet directly coated witha clear paint layer to which a colored design is given bytransfer-printing in Example 3;

[0027]FIG. 3A is a sectional view of a metal sheet coated with abasecoat paint layer and a transparent or translucent topcoat paintlayer to which a colored design is given by transfer-printing in Example5;

[0028]FIG. 3B is a sectional view of a metal sheet coated with abasecoat paint layer, a primer paint layer and a transparent ortranslucent topcoat paint layer to which a colored design is given bytransfer-printing in Example 5;

[0029]FIG. 3C is a sectional view of a metal sheet directly coated witha transparent or translucent topcoat paint layer to which a coloreddesign is given by transfer-printing in Example 5.

DETAILED DESCRIPTION OF THE INVENTION

[0030] The newly proposed painted metal sheet comprises a substratemetal sheet 1 coated with a transparent or translucent topcoat or clearpaint layer 4, as shown in FIGS. 1A-1C. A basecoat paint layer 2 and aprimer paint layer 3 may be optionally formed between the substratemetal sheet 1 and the topcoat or clear paint layer 4. As far as there isthe topcoat or clear paint layer 4 as the uppermost layer, any paintedmetal sheet, i.e. one (FIG. 1A) having the basecoat paint layer 2between the metal substrate 1 and the topcoat or clear paint layer 4,another one (FIG. 1B) having the basecoat paint layer 2 and the primerpaint layer 3 between the metal substrate 1 and the topcoat paint layer4, or still another one (FIG. 1C) having the topcoat paint layer 4directly formed on the metal substrate 1, may be used fortransfer-printing a design with a sublimation dye. In any case, metallicluster of the substrate metal sheet 1 or a color tone of the basecoatpaint layer 2 or the primer paint layer 3 may be used as a backgroundfor the printed design realized by penetration of a sublimation dye intothe topcoat or clear paint layer 4.

[0031] The basecoat paint layer 2 may be white or colored with a propertone. When metallic luster of the substrate metal 1 or a color tone ofthe basecoat paint layer 2 or the primer paint layer 3 is used as abackground for an image of a printed design, a topcoat paint for thelayer 4 is conditioned to a composition with good transparency. In thissense, the term “topcoat paint layer” includes a clear paint layer. Ofcourse, such a filler as silica may be added to the topcoat paint torealize delustered appearance.

[0032] There are not any special restrictions on the kind of substratemetal 1. For instance, a cold-rolled steel sheet, a galvanized steelsheet, a stainless steel sheet, a copper sheet, an aluminum sheet or thelike may be used as the substrate metal 1. In order to realize a designwith metallic impression, such a lustrous sheet as a stainless, aluminumor copper sheet is preferably used. The substrate metal sheet 1 isoptionally subjected to mechanical polishing, pickling and such chemicalconversion treatment as phosphating or chromating in response to a kindand surface condition of the metal sheet 1 before application of anundercoat or topcoat paint, so as to enhance adhesiveness of a paintlayer.

[0033] A basecoat paint layer 2 and a primer paint layer 3 areoptionally formed on the pretreated substrate metal sheet 1 according toan ordinary method.

[0034] The basecoat paint layer 2 is preferably of 10-20 μm in thicknessto shield the substrate metal sheet 1 or the primer paint layer 3. Ifthe basecoat paint layer 2 is thinner than 10 μm, its shielding effecton the substrate metal sheet 1 or the primer paint layer 3 is too weakto realize an appearance of the paint layer without influences of colortones of the substrate metal sheet 1 and the primer paint layer 3. Ifthe basecoat paint layer 2 is thicker than 20 μm on the contrary, aresidual solvent in an applied paint is abruptly vaporized duringbaking. Such abrupt vaporization causes occurrence of pinhole defects,so-called “bumping”, in the paint layer.

[0035] A clear paint layer or topcoat paint layer 4 of 5-40 μm inthickness is formed on the substrate metal sheet 1, the basecoat paintlayer 2 or the primer paint layer 3. If the clear paint layer or topcoatpaint layer 4 is thinner than 5 μm, the painted metal sheet is weak ofwear-resistance. If the clear paint layer or topcoat paint layer 4 isthicker than 40 μm on the contrary, a residual solvent in an appliedpaint is abruptly vaporized during baking. Such abrupt vaporizationcauses occurrence of “bumping” in the paint layer. An excessively thickclear paint layer 4 is also poor of transparency, so that metallicluster of the substrate metal sheet 1 as well as color tones of thepaint layers 2, 3 can not be used as a background for a printed design.

[0036] Thickness of the topcoat paint layer 4 is preferably adjustedwithin a range of 10-25 μm for balancing slippage-proof withwear-resistance. A clear paint layer may be further formed on thetopcoat paint layer 4 for such a use as a flooring sheet which will besubjected to severe abrasive conditions. The topcoat paint 4 may behardened by addition of such a curing agent as melamine, urea orisocyanate.

[0037] The topcoat paint layer 4 is made from a resin, which is easilycolored due to its affinity with a sublimation dye transferred from atransfer film. In this sense, a thermosetting polyester resin havingnumber average molecular weight of 1000-10000 and a glass transitiontemperature (Tg) of 20-60° C. and containing melamine at a ratio of20-150 parts by weight on the basis of 100 parts by weight of a solidcomponent in the resin is well colored with the sublimation dye, and arealized design also has good storage stability. The thermosetting resinis not too softened at a heating temperature of 150-200° C. duringtransfer-printing. The thermosetting resin with good heat resistancealso effectively inhibits deterioration of luster of the painted sheetafter transfer-printing.

[0038] A resin paint for the topcoat paint layer 4 may be a vinyl resinsuch as polyvinyl alcohol, polyvinylbutyral, polyvinylacetal, polyvinylacetate, polyvinylchloride, polyvinylpyrrolidone, polystyrene, anacrylic resin such as polymethyl(metha)acrylate,polybutyl(metha)acrylate, polyacrylamide, polyacrylonitrile, a polyesterresin, a polycarbonate resin, a polyurethane resin, a polyamide resin,an urea-formaldehyde resin, a polycaprolactone resin, a polyarylateresin, a polysulfone resin, a silicone polyester resin, epoxy resin, orthese copolymer or mixture. Especially, a polyester resin is preferablyadded as at least one component to the topcoat paint, since it is wellcolored with the sublimation dye, and a realized design has good storagestability.

[0039] A thermosetting polyester resin is synthesized bypolycondensation of a dibasic acid with a polyalcohol. The dibasic acidmay be aromatic dicarboxylic acid, aliphatic dicarboxylic acid or thoseacid nonhydrates. For instance, one or more of phthalic anhydride,orthophtalic acid, isophthalic acid, terephthalic acid, maleic acid,maleic anhydride, fumaric acid, adipic acid are used as the dibasicacids. In order to improve light-resistance of the paint layer, thethermosetting polyester resin preferably contains phthalic anhydrideand/or orthophtalic acid which forms the 1,2-benzene-dicarbonylstructure. Adipic acid, which does not involve a phenyl group, is also afavorable dibasic acid.

[0040] The polyalcohol may be one or more of ethylene glycol, diethyleneglycol, triethyleneglycol, propylene glycol, pentyl glycol,neopentylglycol or trimethylolethane. A glycol such as pentyl glycolhaving a long aliphatic chain is preferred in order to improve lightresistance of the paint layer. Especially, neopentylglycol, which formsa 2,2-dimethyl trimethylene structure after polymerization, is apreferred polyalcohol.

[0041] Number average molecular weight of the thermosetting polyesterresin is adjusted to 1000-10000. If the number average molecular weightis less than 1000, the topcoat paint layer 4 is poor of elongation andplasticity. If the number average molecular weight exceeds 10000, thetopcoat paint layer 4 is easily decomposed by ultraviolet irradiationdue to decrease of cross-linked parts with the melamine. The melamine asa curing agent is stable as such against ultraviolet irradiation, andeffectively improves light-resistance of the polyester resin paint.

[0042] The effect of the melamine on light-resistance is distinctlynoted by addition of the melamine at a ratio of 20 parts by weight ormore. However, excessive addition of the melamine at a ratio more than150 parts by weight unfavorably increases density of cross-linked partsand causes occurrence of crackings in the paint layer during working. Aglass transition temperature (Tg) of the thermosetting polyester resinis adjusted at a value higher than 20° C. to ensure proper hardness ofthe paint layer for inhibition of crackings. However, a glass transitiontemperature (Tg) higher than 60° C. makes the paint layer too hard andpoor of plasticity.

[0043] Glass flakes 6 of 8 μm or less in thickness and 10-70 μm inaverage length can be dispersed in the topcoat paint layer 4 at a ratioof 5-25 wt. % in order to increase hardness of the topcoat paint layer4. If the ratio of the glass flakes 6 is less than 5 wt. %, the topcoatpaint layer 4 is softer than F by a pencil hardness test. Insufficientdispersion of the glass flakes also causes dappled ruggedness (i.e. poorexternal appearance) of the topcoat paint layer 4 due to scattering ofthe glass flakes on the topcoat paint layer 4. If the glass flakes aredispersed at a ratio more than 25 wt. % on the contrary, the topcoatlayer 4 is opaque and lacks smoothness.

[0044] The glass flakes 6 dispersed in the topcoat paint layer 4 areadjusted to a shape of 8 μm or less in thickness and 10-70 μm in lengthaccounting requisition for the topcoat paint layer and coatingoperation. If glass flakes thicker than 8 μm are dispersed in thetopcoat paint layer 4, the topcoat paint layer 4 is easily cracked whenthe painted metal sheet is bent and also peeled off the substrate metalsheet 1 due to abrasion. Such thick glass flakes put harmful influenceson coating operation, since they are apt to create sediment in thetopcoat paint. If the glass flakes are longer than 70 μm in average,such longer glass flakes are projected from a surface of the topcoatpaint layer 4 and easily dropped out. If the glass flakes are shorterthan 10 μm on the contrary, it is difficult to adjust a surface of thetopcoat paint layer 4 to controlled ruggedness more than Ra 1.0 μm.

[0045] Calcium silicate 7 of 1-8 μm in average primary particle size isfurther dispersed in the topcoat paint layer 4. The primary particles ofcalcium silicate filler to secondary particles of 15-50 μm in thetopcoat paint, and the secondary particles are dispersed in the topcoatpaint layer 4 to improve slippage-proof. If the calcium silicate is ofprimary particle size bigger than 8 μm, the secondary particles are aptto sediment in the topcoat paint, resulting in poor coating operability.If the calcium silicate is of primary particle size smaller than lm onthe contrary, resultant secondary particles are too small to obtain aslippage-proof topcoat paint layer 4.

[0046] Calcium silicate 7 is dispersed in the topcoat paint layer 4 at aratio of 0.5-10 wt. % (preferably 1.5-5 wt. %). The slippage-proofproperty of the topcoat paint layer 4 is distinctly noted by dispersionof calcium silicate at a ratio of 0.5 wt. % or more. However, excessivedispersion of calcium silicate at a ratio more than 10 wt. % weakenstransparency of the topcoat paint layer 4, so that metallic luster ofthe substrate metal sheet 1 or a color tone of an undercoat paint layercan not be used as a background for a printed design.

[0047] The topcoat layer 4 is preferably adjusted to hardness of 2H orharder as a cured state. The topcoat paint layer 4 can be hardened inshort time by addition of such a curing agent as methylated or butylatedmelamine or a curing catalyst such as a sulfonic compound to cure thetopcoat paint layer 4. The topcoat paint layer 4 preferably has a colortone with the highest possible transparency, in the case where metallicluster of the substrate metal sheet 1 or a color tone of an undercoatpaint layer is used as a background for a printed design.

[0048] Powdery silica 8 of 0.5-8 μm in average particle size may bedispersed in a clear paint layer 4, as shown in FIGS. 2A-2C. The clearpaint layer 4 is hardened to F or harder by dispersion of powdery silica8 bigger than 0.5 μm to improve anti-scratching property andwear-resistance. Dispersion of the powdery silica 8 also effectivelyincreases coloring concentration of a sublimation dye. However,dispersion of powdery silica bigger than 8 μm in the clear paint layer 4causes occurrence of crackings in the clear paint layer 4 during bendingthe painted metal sheet as well as peeling of the clear paint layer 4due to abrasion. Such bigger silica particles are also unfavorable forpenetration of a sublimation dye with good coloring concentration.

[0049] The powdery silica 8 is dispersed in the clear paint layer 4 at aratio of 1-10 wt. %. The anti-scratching property of the clear paintlayer 4 is distinctly noted by dispersion of the powdery silica at aratio of 1 wt. % or more. If the powder silica is quantitativelyinsufficient, a surface of the clear paint layer 4 is changed to a statehaving a glossiness value of 75 or more where scratches areconspicuously distinguished. However, excessive dispersion of thepowdery silica at a ratio more than 10 wt. % decreases glossiness of theclear paint layer 4 to a value below 10 and weakens transparency of theclear paint layer 4. Consequently, metallic luster of the substratemetal sheet 1 or a color tone of the basecoat paint layer 2 or theprimer paint layer 3 can not be used as a background for a printeddesign. Excessive dispersion of the powdery silica causes occurrence ofcrackings in the clear paint layer during bending of the painted metalsheet. The glossiness value of the clear paint layer 4 is preferablyadjusted to 40-60 in case of using the metallic luster of the substratemetal sheet, or 10-30 in case of using the basecoat paint layer 2 or theprimer paint layer 3 to make crackings inconspicuous.

[0050] An effect of the powdery silica 8 on coloring concentration ofthe sublimation dye is distinctly noted by dispersion of the powderysilica 8 at a ratio of 1 wt. % or more, but the coloring concentrationis made constant in regard to silica content when the powdery silica isdispersed at a ratio exceeding 10 wt. %. From many experiments, theinventors suppose the reason why coloring concentration is enhanced bydispersion of powdery silica as follows:

[0051] A sublimation dye is apt to excessively transfer, in the casewhere a printed design is given to a painted metal sheet bytransfer-printing with a heat. When a transfer film textile-printed witha sublimation dye is laid on a painted metal sheet and heat-treated,some parts of the sublimated dye excessively move to an undercoat paintlayer, and other parts return to the transfer film. The excessivemovement of the dye is suppressed by the powdery silica 8 dispersed inthe clear paint layer 4. Minute cavities are generated in and on theclear paint layer 4 due to dispersion of the powdery silica 8, so thatthe dye preferentially transfers along a thickness direction of theclear paint layer 4 rather than a surface direction. This preferentialtransfer of the dye increases coloring concentration, resulting inrealization of an impressive printed design with high contrast.

[0052] A transfer film textile-printed with a sublimation dye is laid ona painted metal sheet and heated in contact with the topcoat or clearpaint layer 4. A sublimated dye penetrates into the transparent ortranslucent paint layer 4 so as to form a part 5 colored with the dyewhich extends along a thickness direction of the paint layer 4. As aresult, a colored design full of three-dimensional impression isrealized with high contrast.

[0053] The transfer film may be prepared by gravure, offset orscreen-printing. An electrophotography and electrographic recording, inkjet or heat-sensitive transfer-printing method using the computergraphics without necessity of the plate making step may be adopted incase of short-lot production, since an objective design is provided asoccasion demands without stock burden. In addition, the printed designis not diminished, since the colored parts 5 are formed in the topcoator clear paint layer 4. It is not necessary to cover the printed designwith a transparent film after transfer-printing due to good stability ofthe printed design. By comparison, a conventional laminated metal sheetis likely delaminated due to sole presence of colored parts between atopcoat or clear paint layer and the substrate metal sheet.

[0054] The sublimation dye is one which can transfer due to sublimationor vaporization in a heated state. The term “sublimation” in thisspecification involves vaporization from a liquid phase. The sublimationdye is selected from dispersion-type dyes such as quinophthalonederivatives, anthraquinones and azo pigment, for instance. Of course,various sublimation dyes conventionally used for thermally sublimatingtransfer or sublimating transfer textile-printing are also used forprinting the topcoat or clear paint layer 4 without any restrictions ontheir kinds.

[0055] Yellow dyes useful as sublimation dyes for transfer-printing apainted metal sheet are Kayaset Yellow AG, Kayaset Yellow TDN (offeredby NIPPON KAYAKU Co., Ltd.), RTY 52, Dianix Yellow 5R-E, Dianix YellowF3G-E, Dianix Brilliant Yellow 5G-E (offer by MITSUBISHI Chemicals Co.,Ltd.), Blast Yellow 8040, DY108 (offered by ARIMOTO Chemicals Co.,Ltd.), Sumikaron Yellow EFG, Sumikaron Yellow E-4GL (offered by SUMITOMOChemicals Co., Ltd.), FORON Brilliant Yellow SGGLPI (offered by SandCo.) and PS Yellow GG (MITSUI TOATSU Dyestuff Co., Ltd.)

[0056] Magenta dyes are Kayaset Red 026, Kayaset Red 130, Kayaset Red B(offered by NIPPON KAYAKU Co., Ltd.), Oil Red DR-99, Oil Red DK-99(offered by ARIMOTO Chemicals Co., Ltd.), Diacelliton Pink B (offered byMITSUBISHI Chemicals Co., Ltd.), Sumikaron Red E-FBL (offered bySUMITOMO Chemicals Co., Ltd.), Latyl Red B (offered by Du Pont Co.),Sudan Red 7B (offered by BASF Co.), Resolin Red FB, Ceres Red 7B(offered by Bayer Co.).

[0057] Cyanic dyes are Kayalon Fast Blue FG, Kayalon Blue FR, KayasetBlue 136, Katacet Blue 906 (offered by NIPPON KAYAKU Co., Ltd.), OilBlue 63 (offered by ARIMOTO Chemicals Co., Ltd.), HSB9, RTB31 (offeredby MITSUBISHI Chemicals Co., Ltd.), Disperse Blue #1 (offered bySUMITOMO Chemicals Co., Ltd.), MS Blue 50 (offered by MITSUI TOATSUDyestuff Co., Ltd.), Ceres Blue GN (offered by Bayer Co.) and DuranolBrilliant Blue 2G (offered by ICI).

[0058] These sublimation dyes for various colors may be solely orcombinatively used for realization of an objective colored design. Ablack tone is gained by properly mixing yellow, magenta and cyanicsublimation dyes. A dye having a sublimation temperature of 60° C. orhigher may be used as a sublimation dye having a color tone other thanyellow, magenta and cyanic tones. A sublimation dye having a highersublimation temperature is preferable for bestowing a paint layer withgood light-resistance and wear-resistance, since such a dye isrelatively of bigger molecular weight.

[0059] The transparent or translucent paint layer 4 can be preventedfrom deterioration of adhesiveness or discoloration caused by permeationof a solar or ultraviolet beam, when an ultraviolet-absorbing agent isadded to the paint layer 4. Such an ultraviolet-absorbing agent shall begood of heat-resistance, anti-sublimation and solubility, preferably anultraviolet-absorbing agent having heat-resistance such that its weightloss is 10 wt. % or less when heated up to 300° C. at a speed of 5°C./minute in the open air. Such an ultraviolet-absorbing agent asbenzotriazole or triazine satisfies the demands. Triazine solely ortogether with benzotriazole is preferably added to a resin paint for thetopcoat or clear paint layer 4. It is also possible that a hinderedamine photostabilizer may be additionally added to the resin paint at aratio of 0-3.0 wt. %.

[0060] A benzotriazole ultraviolet-absorbing agent may beoctyl-3-[3-t-butyl-5-(2H-benzotriazole-2-yl)-4-hydroxyphenyl]propinate(offered as TINUVIN 384 by Ciba-Geigy Co.),2-[2-hydroxy-3,5-bis(α,α′dimethylbenzyl)phenyl]-2H-benzotriazole(offered as TINUVIN 900 by Ciba-Geigy Co.). a condensation product(offered as TINUVIN 1130 by Ciba-Geigy Co.) ofmethyl-3-[3-t-butyl-5-(2H-benzotriazole-2-yl)-4-hydroxyphenyl propinatewith polyethylene glycol of approximately 300 molecular weight,2-[2′-hydroxy-3′-(3″,4″,5″,6″-tetrahydro phthalimidemethyl)-5′-methylphenyl]-benzotriazole (offered as Viosorb 590 by KTODOHPharmaceuticals Co., Ltd.).

[0061] A triazine ultraviolet-absorbing agent may be a mixture (offeredas TINUVIN 400 by Ciba-Geigy Co.) of2-[4-[(2-hydroxy-3-di-decyloxypropyl)-oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazinewith2-{4-[2-hydroxy-3-tridecyloxypropyl]-oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl-1,3,5-triazine).

[0062] These ultraviolet-absorbing agents may be solely or combinativelyadded to a topcoat resin paint at a ratio of 1-22 wt. % on the basis ofa non-volatile component in the resin paint. If theultraviolet-absorbing agent is added at a ratio more than 22 wt. %, thepaint layer 4 is likely deteriorated in anti-fouling property,plasticity and external appearance. In addition, the paint layer 4 istoned with a color derived from the ultraviolet-absorbing agent.

[0063] A hindered amine photostabilizer may be optionally added to aresin paint at a ratio of 3 wt. % or less based on a non-volatilecomponent in the resin paint in order to further improvelight-resistance of the topcoat or clear paint layer 4. Such a hinderedamine may be bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (offered asSANOL LS770 by SANKYO Co., Ltd.), bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate (offered as SANOL LS765 by SANKYO Co., Ltd.),1-{2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl}-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine(offered as SANOL LS2626 by SANKYO Co., Ltd.),4-benzoyloxy-2,2,6,6-tetramethylpiperidine (offered as SANOL LS744 bythe SANKYO Co., Ltd.),8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triaza spiro [4,5]decane-2,4-dione (offered as SANOL LS440 SANKYO Co., Ltd.),2-[3,5-di-t-hydroxybenzyl-2-n-butyl malonic acidbis(1,2,2,6,6-pentamethyl-4-piperidyl)] (offered as TINUVIN144 byCiba-Geigy Co.), succinic acid bis(2,2,6,6-tetramethyl-4-piperidyl)ester(offered as TINUVIN780FF by Ciba-Geigy Co.), a polycondensation product(offer as TINUVIN 622 LD by Ciba-Geigy Co.) of succinic acid dimethylwith 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, poly{[6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]} (offered as CHIMASSORB 944LDby Ciba-Geigy Co.), a polycondensation product (offered as CHIMASSORB119 FL by Ciba-Geigy Co.) of N,N′-bis(3-aminopropyl)ethylenediamine with2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine,bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (offered as TINUVIN 292by Ciba-Geigy Co.), bis(1-octaoxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate (offered as TINUVIN 123 by Ciba-Geigy Co.), HA-70G (offered bySANKYO Co., Ltd.), ADECA STAB LA-52, ADECA STAB LA-57, ADECA STAB LA-62,ADECA STAB LA-63, ADECA STAB LA-67, ADECA STAB LA-68, ADECA STAB LA-82or ADECA STAB LA-87 (offered by ASAHI DENKA KOGYO Co., Ltd.).

[0064] These photostabilizers may be solely or combinatively added to aresin paint at a ratio of 3.0 wt. % or less (preferably 0.5-1.5 wt. %).An effect of the photostabilizer on light-resistance of the paint layer4 is saturated up to a ratio of 3.0 wt. %. Excessive addition of thephotostabilizers causes inferior external appearance of the paint layer4.

[0065] FIGS. 3A-3C depict a painted metal sheet comprising a substratemetal sheet 1 coated with a transparent or translucent topcoat or clearpaint layer 4. A basecoat paint layer 2 and a primer paint layer 3 maybe optionally formed between the substrate metal sheet 1 and the topcoator clear paint layer 4. Colored parts 5 are formed in the topcoat orclear paint layer 4.

EXAMPLE 1

[0066] Production of a Painted Steel Sheet Which has a Topcoat PaintLayer 4 Printed with a Sublimation Dye Directly Formed on a SubstrateSteel Sheet 1 (Samples Nos. 1-11 and Comparative Samples Nos. 1-4, 7-12)

[0067] A stainless steel sheet (SUS 304HL) of 0.5 mm in thickness wasdegreased, cleaned and then chromated. Thereafter, a translucent topcoatpaint was applied to the sheet and baked at 230° C. for 1 minute to forma translucent topcoat resin layer 4 of 16 μm in dry thickness directlyon a substrate steel sheet 1, as shown in FIG. 1C. The topcoat paintused was a polyester resin paint containing glass flakes (of 4-12 μm inthickness and 45-90 μm in length) at a ratio of 3-30 wt. %, calciumsilicate (of 3.5-8 μm in average primary particle size) at a ratio of0.3-12 wt. % and a triazine ultraviolet-absorbing agent (TINUVIN 400 byCiba-Geigy Co.) at a ratio of 6 wt. %, each based on a non-volatilecomponent of the paint.

[0068] A transfer film was prepared by outputting an objective designwith a sublimation dye toner (offered as a sublimable textile-printingtoner by Nippon Steel Chemical Co., Ltd.), onto an electrographicrecording sheet by an image printer (Juana by Exis Co., Ltd.) of anelectrostatic plotter system.

[0069] The transfer film was laid on the topcoat paint layer 4 formed onthe substrate metal sheet 1 and pressed onto the topcoat paint layer 4with a pressure of 50000 Pa at 160° C. for 240 seconds. Thereafter, thetransfer film was separated from the painted steel sheet.

[0070] Production of a painted steel sheet which has a basecoat paintlayer 2 between a substrate steel sheet 1 and a topcoat paint layer 4printed with a sublimation dye (Samples Nos. 12-15 and ComparativeSamples Nos. 5-6)

[0071] A galvanized steel sheet of 0.5 mm in thickness was degreased,cleaned and then chromated. Thereafter, a white polyester resin paintwas applied to the steel sheet and baked at 220° C. for 1 minute to forma white basecoat paint layer 2 of 18 μm in dry thickness. The sametranslucent polyester resin paint as above-mentioned was applied to thebasecoat paint layer 2 and baked at 230° C. for 1 minute to form atranslucent topcoat paint layer 4 of 16 μm in dry thickness. A colordesign was given to the topcoat paint layer 4 using a transfer film inthe same way.

[0072] Fillers dispersed in a topcoat paint layer 4 formed on each steelsheet according to the present invention and comparative tests are shownin Tables 1 and 2, respectively. TABLE 1 FILLERS IN TOPCOAT PAINT LAYERSFORMED ON STEEL SHEET (the present invention) glass flakes calciumsilicate kind of average Average Sample steel content thickness lengthcontent particle No. sheet wt. % μm μm wt. % size μm 1 stainless 20 4 450.5 3.5 2 steel sheet 20 4 45 2.5 3.5 3 (SUS 304) 20 4 45 5.0 3.5 4hair-line 20 4 45 10.0 3.5 5 finished 5 4 45 2.5 3.5 6 10 4 45 2.5 3.5 715 4 45 2.5 3.5 8 25 4 45 2.5 3.5 9 20 8 45 5.0 3.5 10 20 8 45 5.0 8.011 20 4 70 5.0 3.5 12 galvanized 5 4 45 0.5 3.5 13 steel sheet 15 4 452.5 3.5 14 25 4 45 10.0 3.5 15 20 4 70 5.0 8.0

[0073] TABLE 2 FILLERS DISPERSED IN TOPCOAT PAINT LAYERS FORMED ON STEELSHEETS (Comparative Samples) glass flakes calcium silicate averageaverage particle average particle Sample content size thickness lengthcontent size No. kind of steel sheet wt. % μm μm μm wt. % μm 1 stainlesssteel sheet 30 — 4 45 5.0 3.5 2 (SUS 304)  3 — 4 45 5.0 3.5 3 hair-linefinished 15 — 12  45 5.0 3.5 4 15 — 4 90 5.0 3.5 5 galvanized steelsheet 15 — 12  45 5.0 3.5 6 15 — 4 90 5.0 3.5 7 stainless steel sheet 15— 4  8 5.0 3.5 8 (SUS 304) 20 — 4 45 0.3 3.5 9 hair-line finished 20 — 445 12.0  3.5 10* 20 10 — — — — 11* 20 6 — — — — 12* 20 4.5 — — — —

[0074] Each painted steel sheet printed with the colored design wastested to research adhesiveness and hardness of the paint layer,workability, slippage-proof property, wear-resistance, smoothness andtransparency.

[0075] Adhesiveness of the paint layer was examined by a checkeredErichsen test (engraving the paint layer to a checkered pattern and thendrawing it by a length of 6 mm, as regulated in JIS G3320). An adhesivetape was stuck onto the drawn part of a test piece and then peeled off.Peeled states of paint layers were classified to 5 levels to evaluateadhesiveness.

[0076] Workability of the painted steel sheet was examined by a bendingtest piece at a room temperature of 20° C., wherein a test piece wasbent with 180 degrees in the state that one or more sheets having thesame thickness as the test piece were sandwiched. Workability was judgedby the number t of the sandwiched sheets until the paint layer wascracked at the bent part, and evaluated as follows. A painted steelsheet, which was bent at 0-2t without crackings, was excellent (⊚) inworkability. A painted steel sheet, which was cracked in the paint layerat 3-4t, was good (◯) in workability. A painted steel sheet, which wascracked in the paint layer at 5t, was poor (Δ) in workability. A paintedsteel sheet, which was cracked in the paint layer at 6t, was bad (X) inworkability. Such painted steel sheets evaluated as ⊚ or ◯ can beoffered as precoated steel sheets to a market.

[0077] Hardness of the paint layer was examined by a scratching testusing a pencil MITSHUBISHI UNI (offered by MITSHUBISHI Pencil Co.,Ltd.), as regulated in JIS K5499-6-8.4. Hardness was judged by a highestpencil hardness with which the paint layer was not scratched.

[0078] A slippage test was performed using a dynamic slip tester tomeasure static and dynamic friction coefficients. A test piece was stuckto a bottom of a sled metal, and a neoprene rubber of 5 mm in thicknessand 60 in Shore A hardness was stuck onto a slide plate. A weight wasmounted on the sled metal to adjust a total weight to 800 g. The sledmetal was shifted in contact with the slide plate under this condition.A static friction coefficient was calculated from a maximum staticfriction force at the moment when the sled metal began to move, while adynamic friction coefficient was calculated from a dynamic frictionforce at 20 seconds after sliding of the sled metal began.

A static or dynamic friction coefficient=F/P,

[0079] herein F is a maximum static or dynamic friction force,

[0080] P is a total weight of a sled metal and a balance weight.

[0081] Wear-resistance of the painted steel sheet was examined by aTaber abrader. A disk-shaped test piece of 120 mm in diameter, which hadan opening of 6 mm in diameter formed at its center, was fixed to theabrader. After the test piece was rotated 200 times under thiscondition, it was weighed to detect a weight loss caused by abrasion. ATaber value (wear index) was calculated from the detected weight lossaccording to the formula of:

A Taber value=a weight loss (mg)×1000/a rotation number (200)

[0082] Smoothness of a paint layer 4 was measured by a contact-typeroughness meter, and evaluated by an average surface roughness value Raalong a center line

[0083] Transparency of a paint layer 4 was judged by naked eye'sobservation and evaluated as follows: The mark ◯ means good transparencysufficient to use a color tone of a basecoat paint layer 2 as abackground for a printed design. The mark Δ means transparency of apaint layer 4 which was used as a background although a little dimness.The mark X means poor transparency of a paint layer 4 which can not beused as a background for a printed design.

[0084] Test results are shown in Table 3 (the present invention) andTable 4 (Comparative Tests), respectively.

[0085] It is apparently noted from comparison of results in Table 3 withresults in Table 4 that any painted steel sheet printed according to thepresent invention was excellent in all of adhesiveness, hardness,workability, slippage-proof property, smoothness and transparency. Theslippage-proof property became better with increasing of calciumsilicate, although wear-resistance and transparency were degraded alittle. That is, it is understood that a ratio of calcium silicate shallbe determined in response to which property is important for a coatedsteel product among design, wear-resistance and slippage-proof. It isalso noted from Table 3 that the paint layer was harder as glass flakesincreased.

[0086] On the other hand, Comparative Samples were inferior of at leastone of adhesiveness, hardness, workability, slippage-proof property,smoothness or transparency, as shown in Table 4. In actual, ComparativeSample No. 1 was poor of transparency, Comparative Sample No. 2 was lackof hardness, Comparative Samples Nos. 3-6 were inferior of adhesivenessand workability due to inadequate particle size of glass flakes,Comparative Sample No. 7 was insufficient of slippage-proof property dueto dispersion of relatively short glass flakes, Comparative Sample No. 8was insufficient of slippage-proof property due to shortage of calciumsilicate, and Comparative Sample No. 9 was poor of transparency due toexcessive dispersion of calcium silicate. TABLE 3 PROPERTIES OF COATEDSTEEL SHEET PRINTED WITH SUBLIMATION DYE (the present invention)slippage-proof adhesiveness dynamic static wear- surface Sample of paintpencil friction friction resistance a roughness No. layer hardnessWorkability coefficient coefficient Taber value Ra (μm) transparency 1 53H ⊚ 0.32 0.42 15.5 2.6 ◯ 2 5 3H ⊚ 0.47 0.57 14.6 2.5 ◯ 3 5 3H ⊚ 0.510.64 18.7 2.7 Δ 4 5 3H ⊚ 0.62 0.78 25.1 2.4 Δ 5 5 2H ⊚ 0.44 0.51 11.51.2 ◯ 6 5 2H ⊚ 0.48 0.58 12.1 2.0 ◯ 7 5 3H ⊚ 0.42 0.65 15.0 2.8 ◯ 8 5 3H⊚ 0.40 0.57 19.9 2.4 ◯ 9 4 3H ◯ 0.41 0.59 31.3 3.1 Δ 10 4 2H ◯ 0.48 0.4839.2 3.4 Δ 11 4 2H ◯ 0.47 0.46 22.6 3.2 Δ 12 5 2H ⊚ 0.37 0.50 18.9 1.3 ◯13 5 2H ⊚ 0.46 0.67 11.8 2.5 ◯ 14 5 2H ⊚ 0.67 0.59 32.8 2.2 Δ 15 4 2H ◯0.45 0.51 34.5 3.1 Δ

[0087] TABLE 4 PROPERTIES OF COATED STEEL SHEET PRINTED WITH SUBLIMATIONDYE (Comparative Samples) slippage-proof wear- dynamic static resistancesurface Sample adhesiveness pencil friction friction a Taber roughnessNo. kind of steel sheet of paint layer hardness workability coefficientcoefficient value Ra (μm) transparency 1 stainless steel sheet 4 3H ⊚0.40 0.54 16.3 2.1 X 2 (SUS 304) 5 F ⊚ 0.29 0.37 17.4 1.2 ◯ 3 hair-linefinished 2 2H X 0.45 0.59 43.8 3.1 ◯ 4 2  H X 0.50 0.61 39.5 3.6 ◯ 5galvanized 2 2H X 0.54 0.63 27.9 2.9 ◯ 6 steel sheet 2  H X 0.59 0.6728.4 3.0 ◯ 7 stainless steel sheet 5 2H ⊚ 0.29 0.37 15.6 0.8 ◯ 8 (SUS304) 5 3H ⊚ 0.21 0.29 28.9 2.7 ◯ 9 hair-line finished 5 2H ⊚ 0.48 0.6336.8 2.9 X 10 5 2H ⊚ 0.28 0.29 44.6 1.8 ◯ 11 5 2H ⊚ 0.26 0.28 45.9 0.7 ◯12 5 2H ⊚ 0.24 0.27 49.8 0.6 Δ

EXAMPLE 2

[0088] Production of a Coated Steel Sheet Having a Basecoat Paint Layer2 on Which a Topcoat Paint Layer 4 was Formed and Printed with aSublimation Dye (Samples Nos. 16-27, Comparative Samples Nos. 13-17)

[0089] A galvanized steel sheet of 0.5 mm in thickness was degreased,cleaned and then chromated. Thereafter, a white polyester resin paintwas applied to the sheet and baked at 220° C. for 1 minute to form awhite base coat paint layer 2 of 18 μm in dry thickness. A topcoatpolyester resin paint was further applied to the basecoat paint layer 2and baked at 230° C. for 1 minute to form a translucent paint layer 4 of16 μm in dry thickness.

[0090] The topcoat resin paint for Samples Nos. 16-17 and ComparativeSample No. 13 was prepared by adding glass flakes (of 4 μm in thicknessand 45 μm in length) at a ratio of 20 wt. %, calcium silicate (of 3.51μm in average primary particle size) at a ratio of 5 wt. %, a triazineultraviolet-absorbing agent (TINUVIN 400 by Ciba-Geigy Co., Ltd.) and/ora benzotriazole ultraviolet-absorbing agent (TINUVIN 384 by Ciba-GeigyCo., Ltd.) at a ratio of 0-9 wt. % and a hindered amine photostabilizer(TINUVIN 123 by Ciba-Geigy Co., Ltd.) at a ratio of 1.5 wt. %, eachbased on a non-volatile component of a polyester resin. A topcoat resinpaint for Comparative Samples Nos. 14-17 was prepared by addition of abenzophenone ultraviolet-absorbing agent (Viosorb 130 by KYODOHPharmaceuticals Co., Ltd.) instead of the triazine and/or benzotriazoleultraviolet-absorbing agent at a ratio of 1-9 wt. % based on anon-volatile component of a polyester resin.

[0091] Before preparation of the topcoat paint, eachultraviolet-absorbing agent was tested by thermogravimetric analysis,wherein the ultraviolet-absorbing agent was heated up to 300° C. at 5°C./minute and its weight loss was measured. A weight loss of eachultraviolet-absorbing agent was as follows: 3.5 wt. % for triazine, 5wt. % for benzotriazole and 33 wt. % for benzophenone. The resultsproved that the triazine and benzotriazole ultraviolet-absorbing agentswere superior of wear- and heat-resistance.

[0092] A transfer film was prepared by outputting an objective designwith a sublimation dye toner (a sublimable textile-printing toner byNippon Steel Chemical Co., Ltd.) made from a cyanic dye (C. I. DisperseBlue 26 by MITSHUBISHI Chemicals Co., Ltd.) onto an electrographicrecording sheet by an image printer (Juana by Exis Co., Ltd.) of anelectrostatic plotter system, to realize a wholly cyanic pattern.

[0093] The transfer film was laid on the topcoat paint layer 4 of thecoated steel sheet and pressed onto the topcoat paint layer 4 with apressure of 50000 Pa at 160° C. for 240 seconds. Thereafter, thetransfer film was separated from the painted steel sheet. Since thecyanic dye is weakest of light-resistance among various cyanic, magentaand yellow dyes which sublimate under the same conditions, effects ofthe ultraviolet-absorbing agent and the photostabilizer were accuratelyevaluated by use of the cyanic dye.

[0094] Evaluation of Coated Steel Sheets Printed with Sublimation Dyes

[0095] A test piece cut off each painted steel sheet printed with asublimation dye was subjected to a light-resistance test as follows: Thetest piece was held 240 hours at 63° C. in a state irradiated 60 minuteswith a ultraviolet beam from a carbon arc weather meter while sprayingfresh water 12 minutes during holding. A cyanic color tone of the testpiece was measured after the holding, and compared with a color tone ofan unexamined test piece to calculate a color difference AE. Such acolor difference AE is preferably kept less than 7 for using a paintedsteel sheet as an outdoor member for 3 years or longer. A painted steelsheet, which exhibits a color difference AE above 10, is not practicallyused as an outdoor member.

[0096] Adhesiveness of the topcoat paint layer 4 and workability of thecoated steel sheet were also researched in the same way as Example 1,after the light-resistance test.

[0097] Test results are separately shown in Table 5 (the presentinvention) and Table 6 (Comparative Samples).

[0098] Samples according to the present invention were excellent in allof light-resistance, adhesiveness of paint layers and workability, asshown in Table 5. It is apparently noted that addition of a triazineultraviolet-absorbing agent together with a benzotriazoleultraviolet-absorbing agent effectively improved light-resistance of thecolored design, compared with sole addition of a triazine orbenzotriazole ultraviolet-absorbing agent.

[0099] On the other hand, Comparative Sample No. 13 was inferior in allof light-resistance, adhesiveness of a paint layer and workability.Comparative Samples Nos. 14-17 having paint layers, to which abenzophenone ultraviolet-absorbing agent was added instead of a triazineor benzotriazole ultraviolet-absorbing agent, were insufficient oflight-resistance. TABLE 5 PROPERTIES OF TOPCOAT PAINT LAYERS (thepresent invention) ultraviolet- results of light-resistance testabsorbing agent (240 hours, at 63° C.) kind color Sample and contentsdifference Adhesiveness work- No. ratio wt. % ΔE of paint layers ability16 Triazine 10 6.1 5 ⊚ 17 3.0 4.0 5 ⊚ 18 6.0 2.9 5 ⊚ 19 9.0 2.2 5 ⊚ 20Benzotriazole 1.0 6.8 5 ⊚ 21 3.0 4.7 5 ⊚ 22 6.0 3.5 5 ⊚ 23 9.0 2.9 5 ⊚24 triazine and 1.0 5.9 5 ⊚ 25 benzotriazole 3.0 3.7 5 ⊚ 26 at a ratioof 1:1 6.0 2.5 5 ⊚ 27 9.0 2.0 5 ⊚

[0100] TABLE 6 PROPERTIES OF TOPCOAT PAINT LAYERS (Comparative Samples)results of light-resistance test ultraviolet- (240 hours, at 63° C.)absorbing agent color Sample contents difference adhesiveness work- No.kind wt. % ΔE of paint layers ability 13 no addition 0 21.2 3 X 14benzophenone 1.0 15.4 4 Δ 15 3.0 13.4 5 ◯ 16 6.0 11.3 5 ◯ 17 9.0 10.1 5⊚

EXAMPLE 3

[0101] Production of a Painted Steel Sheet Which has a Topcoat PaintLayer 4 Printed with a Sublimation Dye Directly Formed on a SubstrateSteel Sheet 1 (Samples Nos. 1-6 and Comparative Samples Nos. 1-4,7-12)

[0102] A stainless steel sheet (SUS 304HL) of 0.5 mm in thickness wasdegreased, cleaned and then chromated. Thereafter, a translucent topcoatpaint was applied to the sheet and baked at 230° C. for 1 minute to forma translucent topcoat resin layer 4 of 12 μm in dry thickness directlyon a substrate steel sheet 1, as shown in FIG. 2C. The topcoat paintused was a polyester resin paint containing powdery silica 8 (of 0.3-1.2μm in average particle size) at a ratio of 0.5-15 wt. %, and a triazineultraviolet-absorbing agent (TINUVIN 400 by Ciba-Geigy Co.) at a ratioof 3 wt. %, each based on a non-volatile component of the paint.

[0103] Production of a painted steel sheet having a basecoat paint layer2 on which a clear paint layer 4 printed with a sublimation dye wasformed (Samples Nos. 7-12 and Comparative Samples Nos. 5-8)

[0104] A galvanized steel sheet of 0.5 mm in thickness was degreased,cleaned and then chromated. Thereafter, a white polyester resin paintwas applied to the steel sheet and baked at 220° C. for 1 minute to forma white basecoat paint layer 2 of 15 μm in dry thickness. The sametranslucent polyester resin paint as above-mentioned was applied to thebasecoat paint layer 2 and baked at 230° C. for 1 minute to form atranslucent topcoat paint layer 4 of 12 μm in dry thickness. A colordesign was given to the topcoat paint layer 4 by transfer-printing usinga transfer film in the same way.

[0105] Dispersion of powdery silica in the clear paint layer 4 of eachcoated steel sheet is shown in Table 7. TABLE 7 POWDERY SILICA ADDED ASFILLERS DISPERSED IN CLEAR PAINT LAYERS OF COATED STEEL SHEETS powderysilica average Sample kind of substrate contents particles size NOTE No.steel sheet wt. % μm PRESENT 1 stainless steel sheet 1.0 2.5 INVENTION 2(SUS 304), 2.5 2.5 3 hair-line finished 5.0 2.5 4 10.0 2.5 5 5.0 0.5 65.0 8.0 7 galvanized 1.0 2.5 8 steel sheet 2.5 2.5 9 5.0 2.5 10 10.0 2.511 5.0 0.5 12 5.0 8.0 COMPARATIVE 1 stainless steel sheet 0.5 2.5 TESTS2 (SUS 304), 15.0 2.5 3 hair-line finished 5.0 0.3 4 5.0 12.0 5galvanized 0.5 2.5 6 steel sheet 15.0 2.5 7 5.0 0.3 8 5.0 12.0

[0106] Transfer-Printing with a Sublimation Dye

[0107] A transfer film prepared in the same way as Example 1 was pressedonto the topcoat paint layer 4 with a pressure of 50000 Pa at 160° C.for 240 seconds. Thereafter, the transfer film was separated from thepainted steel sheet.

[0108] Evaluation of Coated Steel Sheets Printed with Sublimation Dyes

[0109] A test piece cut off each coated steel sheet was offered to thesame tests as Example 1 to research adhesiveness and hardness of atopcoat paint layer, workability and transparency. In this Example 3,reflection intensity and glossiness of the clear paint layer were alsotested as follows.

[0110] Reflection density from the clear paint layer 4 printed with acyanic dye was measured by a reflection intensimeter (Color CheckerSERIES 1200 by Macbeth Co.).

[0111] Glossiness was judged from reflectivity measured by emitting alight beam to a test piece with incidence and reflection angles of 60degrees, and detecting reflected rays with a specular reflectivitydetector.

[0112] Brightness (a value L) at a cyanic colored part was measured inorder to research an effect of powdery silica on glossiness, andtransparency of the paint layer 4 was evaluated by a lightnessdifference ΔL calculated according to the formula of:

ΔL=L ₁ −L ₀,

[0113] wherein, L₁ is a value L of a coated steel sheet, and

[0114] L₀ is a value L of a coated steel sheet having a paint layer 4which did not contain powdery silica

[0115] Test results are shown in Table 8. It is noted that any Sampleaccording to the present invention was excellent in all of adhesiveness,pencil hardness, workability, wear-resistance, reflection density,glossiness and transparency. As increase of powdery silica dispersed inthe paint layer, the paint layer was more hardened, but itswear-resistance and transparency were degraded a little bit.

[0116] On the other hand, Comparative Samples were inferior of at leastone of adhesiveness, pencil hardness, workability, wear-resistance,reflection density, glossiness and transparency. That is, ComparativeSamples Nos. 1 and 5 had excessively glossy surfaces, on which scratcheswere apparently distinguished, due to insufficient dispersion of powderysilica. Comparative Samples Nos. 2 and 6 were poor of transparency andworkability due to excessive dispersion of powdery silica. ComparativeSamples Nos. 3 and 7 lacked of hardness for practical use due todispersion of too fine powdery silica. Comparative Samples Nos. 4 and 8had opaque paint layers inferior of wear-resistance due to dispersion ofexcessively large particles of powdery silica. TABLE 8 PROPERTIES OFCOATED STEEL SHEETS Sample adhesiveness pencil reflection transparencywear-resistance NOTE No. of paint layer hardness workability densityglossiness ΔL a Taber value PRESENT 1 5 2H ⊚ 2.1 74.3 3.4 18.7 INVENTION2 5 3H ⊚ 2.2 60.2 4.1 19.6 3 5 3H ⊚ 2.5 35.7 5.2 21.3 4 5 3H ◯ 2.8 15.87.9 25.5 5 5 2H ⊚ 2.5 38.3 6.2 18.4 6 4 3H ◯ 2.4 32.8 6.4 30.7 7 5 2H ⊚2.3 70.4 4.0 17.5 8 5 3H ⊚ 2.5 55.0 5.1 19.0 9 5 3H ⊚ 2.9 31.9 6.2 21.710 5 3H ◯ 3.1 11.2 9.2 26.1 11 5 2H ⊚ 2.9 33.4 6.8 17.6 12 4 3H ◯ 3.029.1 7.0 31.3 COMPARATIVE 1 5 F ⊚ 1.5 82.5 1.6 25.3 2 4 3H X 2.8 8.313.8 33.6 3 5 F ⊚ 1.8 40.1 6.8 23.5 4 3 3H X 1.8 30.6 8.2 42.1 5 5 F ⊚1.7 77.5 3.9 24.6 6 4 3H X 3.1 6.0 15.2 34.1 7 5 F ⊚ 2.5 35.7 7.5 24.2 83 3H X 2.6 28.3 9.2 43.7

EXAMPLE 4

[0117] Production of a Coated Steel Sheet Having a Basecoat Paint Layer2 on Which a Clear Paint Layer 4 was Formed and Printed with aSublimation Dye (Samples Nos. 13-21, Comparative Samples Nos. 9-12)

[0118] A galvanized steel sheet of 0.5 mm in thickness was degreased,cleaned and then chromated. Thereafter, a white polyester resin paintwas applied to the sheet and baked at 220° C. for 1 minute to form awhite base coat paint layer 2 of 15 μm in dry thickness. A topcoatpolyester resin paint was further applied to the basecoat paint layer 2and baked at 230° C. for 1 minute to form a translucent paint layer 4 of12 μm in dry thickness.

[0119] The topcoat resin paint for Samples Nos. 13-21 and ComparativeSample No. 9 was prepared by adding powdery silica (of 2.5 μm in averageparticle size) at a ratio of 5.0 wt. %, a triazine ultraviolet-absorbingagent (TINUVIN 400 by Ciba-Geigy Co., Ltd.) and/or a benzotriazoleultraviolet-absorbing agent (TINUVIN 384 by Ciba-Geigy Co., Ltd.) at aratio of 0-6 wt. % and a hindered amine photostabilizer (TINUVIN 123 byCiba-Geigy Co., Ltd.) at a ratio of 1.5 wt. %, each based on anon-volatile component of a translucent polyester resin. A topcoat resinpaint for Comparative Samples Nos. 10-12 was prepared by addition of abenzophenone ultraviolet-absorbing agent (Viosorb 130 by KYODOHPharmaceuticals Co., Ltd.) instead of the triazine and/or benzotriazoleultraviolet-absorbing agent at a ratio of 1-6 wt. % based on anon-volatile component of the same polyester resin.

[0120] Transfer-Printing

[0121] The same transfer film as in Example 3 was laid on a clear paintlayer 4 of each coated steel sheet and pressed onto the clear paintlayer 4 for 240 seconds at 160° C. with a pressure of 50000 Pa at 160°C. for 240 seconds. Thereafter, the transfer film was separated from thepainted steel sheet.

[0122] A test piece was cut off each Sample or Comparative Sample andoffered to the same light-resistance test as in Example 2. Adhesivenessof each clear paint layer 4 as well as workability of each coated steelsheet were tested in the same way as in Example 1.

[0123] Test results are separately shown in Table 9 (the presentinvention) and Table 10 (Comparative Samples).

[0124] Samples according to the present invention were excellent in allof light-resistance, adhesiveness of paint layers and workability, asshown in Table 9. It is apparently noted that addition of a triazineultraviolet-absorbing agent together with a benzotriazoleultraviolet-absorbing agent effectively improved light-resistance of thecolored design, compared with sole addition of a triazine orbenzotriazole ultraviolet-absorbing agent.

[0125] On the other hand, Comparative Sample No. 9 was inferior in allof light-resistance, adhesiveness and workability, and ComparativeSamples Nos. 10-12 were insufficient of light-resistance. TABLE 9PROPERTIES OF TOPCOAT PAINT LAYERS ultraviolet- after light-resistancetest absorbing agent (500 hours at 53° C.) kind color Sample andcontents difference adhesiveness work- No. ratio wt. % ΔE of paintlayers ability 13 triazine 1.0 7.4 5 ⊚ 14 3.0 4.9 5 ⊚ 15 6.0 4.2 5 ⊚ 16benzotriazole 1.0 7.9 5 ⊚ 17 3.0 6.1 5 ⊚ 18 6.0 4.6 5 ⊚ 19 triazine and1.0 7.1 5 ⊚ 20 benzotriazole 3.0 5.6 5 ⊚ 21 at a ratio of 1:1 6.0 3.8 5⊚

[0126] TABLE 10 PROPERTIES OF CLEAR PAINT LAYERS OF COMPARATIVE SAMPLESultraviolet- after light-resistance test absorbing agent (500 hours at63° C.) kind color Sample and contents difference adhesiveness work- No.ratio wt. % ΔE of paint layers ability  9 no addition 0 22.3 2 X 10benzophenone 1.0 16.5 3 X 11 3.0 14.5 4 Δ 12 6.0 12.4 4 Δ

EXAMPLE 5

[0127] Production of a Coated Steel Sheet for Use as Transfer-Printing

[0128] A galvanized steel sheet of 0.5 mm in thickness was degreased,cleaned and then chromated. Thereafter, a white polyester resin paintwas applied to the sheet and baked at 220° C. for 1 minute to form awhite basecoat paint layer 2 of 14 μm in dry thickness. A clearpolyester resin paint was further applied to the basecoat paint layer 2and baked at 230° C. for 1 minute to form a clear paint layer 4 of 18 μmin dry thickness.

[0129] The clear resin paint was prepared from a polyester resin (numberaverage molecular weight of 500-20000, a glass transition temperature Tgof 10-80° C.) containing melamine at a ratio of 5-70 parts by weight onthe basis of 100 parts by weight of a solid component of the resin. Oneor more of adipic acid, orthophthalic acid, isophthalic acid andterephthalic were added as a dicarboxylic acid monomer. Samples Nos.1-9, 11, 13, 15, 17 and Comparative Samples Nos. 1-7 usedneopentylglycol as a di-alcoholic monomer.

[0130] A triazine ultraviolet-absorbing agent together with abenzotriazole ultraviolet-absorbing agent was added to each clear paint,except Samples Nos. 9, 19 and Comparative Samples Nos. 7, 9, at a ratioof 8 wt. % based on a non-volatile component of the resin. A ratio ofthe triazine ultraviolet-absorbing agent to the ultraviolet-absorbingagent was adjusted to 1:1. A hindered amine photostabilizer was added toall the paints at a ratio of 1.5 wt. %.

[0131] Table 11 shows compositions of a clear paint layer 4 formed on asubstrate steel sheet 1 according to the present invention, while Table12 shows compositions of paint layers 4 of Comparative Samples. TABLE 11COMPOSITIONS OF CLEAR PAINT LAYERS FORMED ON STEEL SHEETS (the presentinvention) a glass transition contents of utraviolet- Sample moleculartemperature (Tg) melamine addition of absorbing agent No. weight ° C.wt. % dicarboxylic acid neopentylglycol wt. % 1 1000 35 70 adipicacid:orthophthalic Yes 8 2 3000 acid = 40:60 3 6000 4 10000 5 3000 22 656 7 35 20 8 150 9 70 0 10 No 8 11 isophthalic Yes 12 acid:orthophthalicNo acid = 60:40 13 terephthalic Yes 14 acid:orthophthalic No acid =80:20 15 terephthalic Yes 16 acid:isophthalic No acid = 50:50 17terephthalic acid = 100 Yes 18 No 19 No 0

[0132] TABLE 12 COMPOSITION OF CLEAR PAINT LAYERS OF COMPARATIVE SAMPLESa glass transition contents of ultraviolet- Sample molecular temperature(Tg) melamine addition of absorbing agent No. weight ° C. wt. %dicarboxylic acid neopentylglycol wt. % 1 500 35 70 adipic yes 8 2 15000acid:orthophthalic 8 3 3000 15 acid = 40:60 4 70 5 35 10 6 200 7 1500070 0 8 terephthalic no 8 9 acid:isophthalic 0 acid = 50:50

[0133] Transfer-Printing

[0134] A transfer film was prepared by spraying a cyanic sublimation dyeink to a whole surface of a film by an ink-jet printer. The transferfilm was laid on a coated steel sheet, pressed thereto for 150 secondsat 160° C. with a pressure 4×10⁴ Pa, and then separated therefrom.

[0135] Evaluation of Coated Steel Sheet Printed with Sublimation Dye

[0136] A test piece was cut off each Sample or Comparative Sample andoffered to the same tests as mentioned above to researchlight-resistance, adhesiveness of a paint layer, and workability. Inthis Example 5, an anti-fouling property and moisture resistance wasalso examined as follows:

[0137] Moisture resistance was examined by a 500-hours humidity test at49° C. regulated in JIS Z0208. After the humidity test, a surface of apaint layer was observed to detect presence or absence of blisters.Moisture resistance of the coated steel sheet was evaluated by presence(X) or absence (◯) of blisters on a paint layer.

[0138] In the anti-fouling test, after red and black lines weredescribed on a paint layer with oily inks, a test piece was left as such24 hours at 20° C. Thereafter, the red and black inks were wiped offwith methanol. A test piece, from which red and black inks werecompletely wiped off without any trace, was evaluated as a point 5(excellent anti-fouling property). A point 3 represents remaining oftrace a little bit, and a point 1 represents remaining of remarkabletrace. If a coated steel sheet has anti-fouling property of a point 2 ormore for the red ink, it is available for practical use.

[0139] Test results are shown in Table 13.

[0140] It is noted that any Sample according to the present inventionwas excellent in all of light-resistance, adhesiveness of a paint layer,workability, anti-scratching property, anti-fouling property andmoisture resistance. Improvement of light-resistance was apparentlynoted in case of using orthophthalic acid and/or neopentylglycol as amonomer.

[0141] On the other hand, Comparative Samples are inferior of at leastone of light-resistance, adhesiveness of a paint layer, workability,anti-fouling property, anti-scratching property and moisture resistance(Table 14). That is, Comparative Sample No. 1 was poor of adhesivenessand workability due to use of a polyester resin having relatively smallmolecular weight. Comparative Samples Nos. 2, 7-9 were insufficient oflight-resistance due to use of a polyester resin having bigger molecularweight. Comparative Sample No. 3 had a paint layer likely to bescratched due to a lower glass transition temperature (Tg). ComparativeSample No. 4 was poor of workability due to a higher glass transitiontemperature (Tg). Comparative Sample No. 5 was inferior oflight-resistance and anti-fouling property due to insufficient contentof melamine. Comparative Sample No. 6 was poor of workability due toexcessive amount of melamine. TABLE 13 PROPERTIES OF PAINTED STEELSHEETS (the present invention) a color difference ΔE after 240- hourslight- adhesiveness anti- anti-fouling Sample resistance of a paintscratching property moisture No. test layer workability property redblack resistance 1 3.5 5 ◯ H 5 5 ◯ 2 5.0 5 ⊚ H 5 5 ◯ 3 5.8 5 ⊚ H 5 5 ◯ 46.3 5 ⊚ H 4 5 ◯ 5 5.5 5 ⊚ H 4 5 ◯ 6 4.4 5 ◯ H 5 5 ◯ 7 6.8 5 ⊚ H 4 5 ◯ 82.9 5 ◯ 2H  5 5 ◯ 9 9.7 5 ⊚ H 5 5 ◯ 10 6.4 5 ⊚ H 5 5 ◯ 11 5.2 5 ⊚ H 5 5◯ 12 6.7 5 ⊚ H 5 5 ◯ 13 5.5 5 ⊚ H 5 5 ◯ 14 7.0 5 ⊚ H 5 5 ◯ 15 6.3 5 ⊚ H5 5 ◯ 16 7.9 5 ⊚ H 5 5 ◯ 17 6.5 5 ⊚ H 5 5 ◯ 18 8.1 5 ⊚ H 5 5 ◯ 19 9.6 5⊚ H 5 5 ◯

[0142] TABLE 14 PROPERTIES OF PAINTED STEEL SHEETS (Comparative Samples)a color difference ΔE after 240- hours light- adhesiveness anti-anti-fouling Sample resistance of a paint scratching property moistureNo. test layer workability property red black resistance 1 3.2 3 X 2H 55 ◯ 2 11.0 5 ⊚ F 4 5 ◯ 3 6.1 5 ⊚ HB 4 5 ◯ 4 4.2 4 X 3H 5 5 ◯ 5 10.5 5 ⊚F 3 4 ◯ 6 2.6 5 Δ H 5 5 ◯ 7 13.1 5 ⊚ F 4 5 ◯ 8 12.4 5 ⊚ F 4 5 ◯ 9 15.3 5⊚ F 4 5 ◯

[0143] A painted metal sheet printed with a sublimable dye according tothe present invention as above-mentioned has a transparent ortranslucent topcoat or clear paint layer, which enables use of metallicluster of a substrate metal sheet or a color tone of an undercoat paintlayer as a background for a printed design. The painted metal sheet isalso excellent in slippage-proof property and wear-resistance. Atransfer-printing method using a sublimation dye is suitable for ashort-lot production of colored metal sheets having designs in responseto various needs. The painted metal sheet is improved in anti-scratchingproperty and wear-resistance by dispersion of powdery silica in thetopcoat or clear paint layer. The painted metal sheet is also improvedin light-resistance by inclusion of melamine in a thermosettingpolyester resin at a controlled ratio, so that a colored design given tothe metal sheet keeps its sharpness without discoloration or fading fora long time. The metal sheets obtained in this way are useful asmulti-colored signboards, decorative interior members, decorativeflooring members, door panels of elevators, and surface panels ofelectric home appliances, surface panels of furniture.

The invention claimed is:
 1. A painted metal sheet which comprises asubstrate metal sheet, a topcoat or clear paint layer of 5-40 μm inthickness, formed on said substrate metal sheet, wherein said topcoat orclear paint layer is used for transfer-printing with a sublimation dyeto realize a colored design and said topcoat or clear paint comprises aresin paint containing glass flakes of 8 μm or less in thickness and10-70 μm in average length at a ratio of 5-25 wt. % and calcium silicateof 1-8 μm in average primary particles size at a ratio of 0.5-10 wt. %,each based on a non-volatile component of said topcoat or clear paint.2. The painted metal sheet of claim 1, wherein the topcoat or clearpaint layer contains a component selected from the group consisting oftriazine ultraviolet-absorbing agents and benzotriazoleultraviolet-absorbing agents.
 3. The painted metal sheet of claim 1,further comprising an undercoat paint layer formed between saidsubstrate metal sheet and said topcoat or clear paint layer.
 4. Thepainted metal sheet of claim 1, further comprising a primer paint layerformed between said substrate metal sheet and said topcoat or clearpaint layer.
 5. The painted metal sheet of claim 1, wherein the topcoator clear paint layer is transparent.
 6. The painted metal sheet of claim1, wherein the topcoat or clear paint layer is translucent.
 7. A paintedmetal sheet, which comprises a substrate metal sheet, a topcoat or clearpaint layer of 5-40 μm in thickness formed on said substrate metalsheet, wherein said topcoat or clear paint layer is used for transferprinting with a sublimation dye to realize a colored design and saidtopcoat or clear paint comprises a resin paint containing powdery silicaof 0.5-8 μm in average particle size at a ratio of 1-10 wt. % based on anon-volatile component of said topcoat or clear paint.
 8. The paintedmetal sheet of claim 7, wherein the topcoat or clear paint layercontains a component selected from the group consisting of triazineultraviolet-absorbing agents and benzotriazole ultraviolet-absorbingagents.
 9. The painted metal sheet of claim 7, further comprising anundercoat paint layer formed between said substrate metal sheet and saidtopcoat or clear paint layer.
 10. The painted metal sheet of claim 7,further comprising a primer paint layer formed between said substratemetal sheet and said topcoat or clear paint layer.
 11. The painted metalsheet of claim 7, wherein the topcoat or clear paint layer istransparent.
 12. The painted metal sheet of claim 7, wherein the topcoator clear paint layer is translucent.
 13. A painted metal sheet, whichcomprises a substrate metal sheet, a topcoat or clear paint layer of5-40 μm in thickness formed on said substrate metal sheet, wherein saidtopcoat or clear paint layer is used for transfer printing with asublimation dye to realize a colored design and said topcoat or clearpaint comprises a resin constituent selected from the group consistingessentially of: i) glass flakes, calcium silicate, and resin; and ii)resin and powdery silica.
 14. The painted metal sheet of claim 13,wherein constituent i further comprises a resin paint containing glassflakes of 8 μm or less in thickness and 10-70 μm in average length at aratio of 5-25 wt. % and calcium silicate of 1-8 μm in average primaryparticle size at a ratio of 0.5-10 wt. % each based on a non-volatilecomponent of said topcoat or clear paint.
 15. The painted metal sheet ofclaim 13, wherein constituent ii further comprises a resin paintcontaining powdery silica of 0.5-8 μm in average particle size at aratio of 1-10 wt. % based on a non-volatile component of said topcoat orclear paint.
 16. The painted metal sheet of claim 13, wherein thetopcoat or clear paint layer contains a component selected from thegroup consisting of triazine ultraviolet-absorbing agents andbenzotriazole ultraviolet-absorbing agents.
 17. The painted metal sheetof claim 13, further comprising an undercoat paint layer formed betweensaid substrate metal sheet and said topcoat or clear paint layer. 18.The painted metal sheet of claim 13, further comprising a primer paintlayer formed between said substrate metal sheet and said topcoat orclear paint layer.
 19. The painted metal sheet of claim 13, wherein thetopcoat or clear paint layer is transparent.
 20. The painted metal sheetof claim 13, wherein the topcoat or clear paint layer is translucent.